Non-linear interplay between exchange-bias-induced unidirectional anisotropy and oblique-deposition-induced uniaxial anisotropy

Abstract

A systematic investigation of the non-linear interplay between the uniaxial magnetic anisotropy induced by oblique deposition and the unidirectional magnetic anisotropy induced by exchange bias coupling in NiFe/MnIr bilayers was performed. It was found that depending on the oblique angle, the uniaxial anisotropy induced by oblique deposition may play a vital role in defining the orientation of exchange bias. In particular, when the oblique angle is in the range from 31°to 45°, the oblique-deposition-induced anisotropy is large enough to reorient the easy axis of exchange bias to the direction perpendicular to the deposition field leading to the appearance of double-shifted loops. When the oblique angle is less than 30°or higher than 45°, normal exchange bias is observed with typical behavior. The dynamic permeability spectra are also presented and discussed in conjunction with the static magnetic properties. © 2013 AIP Publishing LLC.